Lactide is a precursor for poly-lactic acid (PLA), a promising biodegradable thermoplastic. Its synthesis is currently carried out in a chemical process which involves complex purification and prepolymerization. Biocatalysts have moderate operating temperature, high activity and high enantioselectivity, and could be a replacement to the conventional method for an one-step process. Rhizomucor miehei lipase (RML) is suitable for such purposes, but the enzyme lacks enantioselectivity for the substrate S-methyl-lactate to synthesize L-lactide. Enantiopurity is a key factor for good physical characteristics of the PLA product. In this study, rational design of RML was conducted to enhance the enantioselectivity of the enzyme using computational docking of the enzyme and lactides. By comparing L-lactide-RML and D-lactide-RML complexes several mutation site candidates were identified that could specifically enhance the interaction between RML and L-lactide while diminishing the interaction with D-lactide. RML mutants have been expressed in Escherichia coli for a confirmation of the desired enantioselectivity change. Further results will be discussed.
키워드
EnantioselectivityLipaseEnzyme Engineering
저자
Hoe-Suk LEE [ Graduate Program of Bioengineering, Seoul National University, Seoul, 151-744. ]
Young Je YOO [ Graduate Program of Bioengineering, Seoul National University, Seoul, 151-744. ]
한국생물공학회 [The Korean Society for Biotechnology and Bioengineering]
설립연도
1984
분야
공학>생물공학
소개
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